1. Field of the Invention
The present invention relates to an assembly comprising two parts hinged together by a hinge with assisted opening/closing. An assembly of this kind may, in particular, be formed of a stoppering element comprising a body to which a closure cap is hinged. Alternatively, it may be a container comprising a lid hinged to a bottom. A container of this type may be in the form of a case of the make-up type, or of a pot, or in any other form of container which can be closed by a hinged lid.
2. Description of the Related Art
It is known practice, particularly in the case of stoppering elements, for such assemblies to be made in two parts hinged together and obtained by one-piece moulding from materials such as polyethylenes or polypropylenes. The two parts can be folded about a main geometric axis and are connected by film hinges with at least one intermediate element arranged between them. The intermediate element is capable of forming a spring so that, after it has passed through a position of unstable equilibrium, it returns the cap of the stoppering element to the closed or almost closed position, or to the opened position. Such systems, although in widespread use, do have certain drawbacks associated with the complexity and cost of the mold needed to produce them in a single piece. Furthermore, producing these elements as a single piece and therefore generally from one single material makes it necessary to come to a compromise between the properties sought for the stoppering element itself and the properties required of the intermediate element capable of forming the return spring. The result of this compromise is generally that the material is not the optimum material for fulfilling the intermediate-element function. It is therefore frequently found that such hinges experience an appreciable loss of elasticity after they have been used a few times.
However, such one-piece structures are generally considered to operate satisfactorily in the case of caps of the type used for stoppering bottles, particularly of cosmetic products. These caps are semi-rigid, i.e. they have a certain elasticity. In general, the elastic deformability of the two parts connected by the hinge is used to encourage the hinge to act as a spring. However, the use of such hinges becomes more difficult when two rigid pieces, which have appreciably no flexibility or elasticity, have to be hinged together. This is the scenario, in particular, where cases of the make-up type or pots of the cosmetic type are concerned. The constituent parts of such elements may have a mean thickness which may be of the order of a few millimeters and which prevents practically any elastic deformability of the parts adjacent to the hinge. In the case of a cosmetic pot, the lid is generally screw-fastened onto the pot with all the drawbacks associated therewith. With cases where elasticity for opening and/or closing is desired, use is made of auxiliary spring mechanisms which have a substantial impact on the cost price of such cases. Furthermore, the presence of these attached mechanisms is a source of weakness for the case.
Such cases or pots may further comprise a label intended to form a decoration or a support for information, particularly of a technical or commercial nature relating to the product contained therein or to the company marketing them. Depending on the desired decoration or on the amount of information to be printed, it may sometimes be desirable to have a label which extends over the surface of both of the hinged-together elements at the same time. With the conventional hinges used, particularly for cases or pots, it is sometimes difficult to produce such a label in a single piece. This difficulty occurs because that portion of the label which is to lie facing the hinge zone could have a significant effect on the operation of the hinge.
One of the objects of the present invention is to produce a structure with two elements hinged together by a hinge with assisted opening and closing. This structure completely or partially solves the problems discussed hereinabove with reference to the known devices.
A particular object is to produce such a hinge for elements having portions located on each side of the hinge axis with practically no elasticity or elastic deformability.
According to the invention, these objects are achieved by producing an assembly comprising a first part and a second part, said second part being hinged to the first part about an axis lying in a closure plane, and a sheet fixed onto at least a portion of the surface of each of the first and second parts, said sheet comprising at least one connecting strip which, when the assembly is in the closed position, intersects the closure plane without passing through the axis, said connecting strip being capable, at the opening and closing of the assembly, of occupying an intermediate position in which it intersects the axis, and in which it experiences maximum tension, said connecting strip being capable, after passing through the intermediate position by a relative movement of the first and second parts in a first direction, of elastically returning the second part to a closed or almost closed position and, after passing through the intermediate position in a direction which is the opposite of the first direction, of elastically returning the second part to an opened position.
Thus, by producing the elastic return element in the form of an attached sheet, it is possible to produce a hinge with assisted opening and closing between two rigid elements, such as the bottom and the lid of a case of the make-up type. The two hinged-together parts may be formed of two pieces which can be molded separately, which appreciably reduces their cost. The sheet may furthermore be sized so that it covers a substantial part of at least one of the parts of the assembly, so as to form a label, either for decorating the corresponding part(s) or for printing information, particularly of a technical or commercial nature. Thus, the spring function of the hinge is fulfilled by an element which at the same time acts as a decoration or as a support for information. When the label has to extend over a substantial portion of the surface of both parts of the assembly, it can be made as a single piece. In the case of certain applications, it may facilitate operations, particularly cutting and/or affixing operations.
According to a specific embodiment, the assembly comprises a connecting strip positioned between two hinge elements defining the axis and arranged one on each side of the connecting strip. According to an alternative, it comprises two connecting strips separated by a hinge element defining the axis. The choice between the embodiments depends to a large extent on the configuration and geometric shape of the two parts which form the assembly and also on the desired elasticity upon opening and closing.
The hinge element(s) may, in particular, consist of film hinges or of hinges with an attached axle, or of the type with an element borne by either the first or second parts, mounted so that it can rotate inside a recess formed in either the bottom or the lid.
The sheet may be made of a thermoplastic chosen, in particular, from polyethylenes, polypropylenes, polyethylene terephthalates and thermoplastic elastomers. This sheet may also be made using woven or nonwoven materials. The thickness of a sheet of this kind may range from a few tenths of a millimeter to one millimeter, or more. This thickness is chosen as a function of the desired elasticity and of the material used.
As a preference, the first and second parts are configured in such a way as to be rigid, particularly around the hinge axis. In other words, they cannot deform elastically to any appreciable extent during opening and closing.
By way of example, the assembly according to the invention forms a stoppering element, said first part forming a body intended to be a container, said body defining at least one opening of the container, said second part being formed of a cap capable of removably closing off the opening.
However, by way of a preferred example, the assembly according to the invention consists of a container, said first part constituting a bottom capable of containing a product and a free edge which defines an opening, said second part forming a lid capable of sealing the opening closed.
As a preference, the container comprises a device capable of allowing the lid to be locked reversibly onto the bottom in the closed position. Such devices are well known, particularly for closing cases, and may include clasps of the type with elastically deformable elements.
Advantageously, the container is produced in the form of a case of an almost flat shape with a bottom that defines at least one compartment for receiving a product, particularly in solid or pulverulent form. The product may, in particular, be a make-up product in pulverulent or compacted form. Such a case may also contain a mirror, advantageously arranged on the inside face of the lid, and an applicator, particularly in the form of a brush or of a puff arranged in a housing in the case which is provided for this purpose.
Alternatively, the container may be in the form of a pot with a wide opening. A pot of this type may be designed for packaging care products or medicinal products in the form of tablets.
As a preference, the sheet covers a substantial part of at least one of the parts. The sheet forms a decoration or a support for information particularly of the logo or trademark type, or of a commercial or technical nature. Such a label is bonded on in the conventional way over its entire surface. It may, in particular, be self-adhesive. However, for reasons of comfort, it may be advantageous to envision the sheet not to be adhesive on its surface which is intended to form the connecting strip. The decoration or information is printed onto the label-forming sheet by any appropriate printing technique, particularly by screen printing. Such printing techniques are well known and therefore require no further detailed description.